Kirosan Observatory


by Kengo KUMA

Mt. Kiro, on the island of Oshima in Ehime Prefecture, has long been famous for its stunning 360-degree views of the Seto Inland Sea. Visible from the top of Mt. Kiro are Kurushima Strait and the Geiyo Islands to the west and north, with the Hiuchinada Sea to the east, and Imabari Port and Imabari City to the south. But the Kirosan Observatory, designed by architect Kuma Kengo and opened in 1994, is as much about the view from the bottom as from the top.


Kuma, who is also the architect behind the New National Stadium for the Tokyo 2020 Olympics, wanted to avoid building a structure that would stand out when people looked at Mt. Kiro. There was just one problem: the top of Mt. Kiro had already been leveled off to create the existing observation park. Kuma decided to try restoring the mountain’s original peak and then building the Kirosan Observatory inside it. The result is an impressive piece of invisible architecture.


Visitors to Kirosan Observatory walk up a long staircase through a slit cut into the top of the mountain. Inside is a structure like an open-topped concrete bunker, with stairs and walkways leading off in different directions. Walking upstairs leads to the top of Mt. Kiro, where visitors can then follow a route designed to mimic the shape of a single pen stroke. Unlike most viewing platforms, there is no single ideal vantage point for all the tourists to queue up for selfies. Each and every part of the route shows a different view of the Seto Inland Sea.

  • The view of the Kurushima Strait from the Observatory / Photo/©SETOUCHI | ARCHI-TOURISM
  • On the way to the Observatory / Photo/©SETOUCHI | ARCHI-TOURISM
  • The whole facility of the Observatory / Photo/©SETOUCHI | ARCHI-TOURISM
  • The stairs lead to the top / Photo/©SETOUCHI | ARCHI-TOURISM
  • The exterior of the Observatory / Photo/©SETOUCHI | ARCHI-TOURISM


487-4 Minamiura Yoshiumicho Imabarishi, Ehime

It is located in the Kirosan Observatory Park.

Free entry / Free car parking